This particular image is one being spread by the Human Right Campaign. The Facebook post HRC created this morning to spread the word about the image has been shared more than 18,000 times.

Human Rights Campaign

Supporters of same-sex marriage (and their friends) are going to be seeing a lot of red today. Thousands of people on social networks - particularly Facebook and Twitter - are changing their profile pictures to an image of a red equal sign, indicating support for same-sex marriage.

This particular image is one being spread by the Human Right Campaign. The Facebook post HRC created this morning to spread the word about the image has been shared more than 18,000 times.

The HRC's photos is in response to two cases the Supreme Court is hearing this week in relation to state and federal laws restricting same-sex marriage. Today, an appeal of California's ban on same-sex marriage (known as Proposition 8) will be heard. Tomorrow, an appeal of the federal Defense of Marriage Act is on the agenda.

The Human Rights Campaign is just one organization that is heavily invested in today's Supreme Court arguments on California's ban on same-sex marriage.

According to its own literature, HRC "advocates on behalf of LGBT Americans, mobilizes grassroots actions in diverse communities, invests strategically to elect fair-minded individuals to office and educates the public about LGBT issues."